PALPI.—Jointed appendages to some of the organs of the mouth in insects and Crustacea.
PAPILIONACEÆ.—An order of plants (see LEGUMINOSÆ), The flowers of these plants are called papilionaceous, or butterfly-like, from the fancied resemblance of the expanded superior petals to the wings of a butterfly.
PARASITE.—An animal or plant living upon or in, and at the expense of, another organism.
PARTHENOGENESIS.—The production of living organisms from unimpregnated eggs or seeds.
PEDUNCULATED.—Supported upon a stem or stalk. The pedunculated oak has its acorns borne upon a footstool.
PELORIA or PELORISM.—The appearance of regularity of structure in the flowers of plants which normally bear irregular flowers.
PELVIS.—The bony arch to which the hind limbs of vertebrate animals are articulated.
PETALS.—The leaves of the corolla, or second circle of organs in a flower. They are usually of delicate texture and brightly coloured.
PHYLLODINEOUS.—Having flattened, leaf-like twigs or leafstalks instead of true leaves.
PIGMENT.—The colouring material produced generally in the superficial parts of animals. The cells secreting it are called pigment-cells.